Apparatus for introducing materials into an open hearth furnace



Feb. 22, 1966 J. w. M GILL 3,236,511

APPARATUS FOR INTRODUCING MATERIALS INTO AN OPEN HEARTH FURNACE Filed Dec. 4, 1962 2 Sheets-Sheet l Water 00! ll/ll l/ Q: //vv/vr0/e JOHN W mam.

BY Mx Attorney Feb. 22, 1966 w. M GILL 3,236,511

APPARATUS FOR INTRODUCING MATERIALS INTO AN OPEN HEARTH FURNACE Filed Dec. 4, 1962 2 Sheets-Sheet 2 IN VE/VTOR JOHN W. M GILL Br ,9 m4L (Z 19126 Attorney United States Patent 3,236,511 APPARATUS FOR INTRODUCING -MATERIALS INTO AN OPEN HEARTH FURNACE John W. McGill, Munhall, Pa., assignor to United States Steel Corporation, a corporation of Delaware FiledDec. 4, .1962,v Ser. No. 242,268 2 Claims. (Cl. 26634) This invention relates toapparatus for introducing materials into an open hearth'furnace and more particularly to introducingoxygen, ore and limestone through the roof of the furnace. The most common way of adding ore and limestone to a steel producing open "hearth furnace is to have the charging machine dump predetermined quantities of this material into the furnace during the working period of the heat in order to remove excess phosphorous, manganese, carbon and silicon. This method of charging takes considerable time so that it adds to the time required to produce the heat. Considerable time is also required for the added solids to dissolve into the slag and react with the molten metal. In an attempt to decrease the time of heat, the solids have been introduced in granular form into the furnace through a single lance in combination with an oxygen stream or through a separate conduit in the lance by means of compressed air. The lance must be lowered 3 to 4 in. below the level of the slag in order to permit the oxygen to clear away the slag and permit the introduction of the solids at the interface of the steel. Oxygen is also introduced when the solids are not being introduced and plugging of the solids opening or openings results from the splashing slag during such periods. It is also necessary to use flexible additive supply lines for these lances and the life of the supply line is short because of the abrasive action of the additives. With a combination oxygen and solids feed lance there is danger of a physical explosion due to friction. Also the simultaneous introduction of oxygen and solids at the same location in the bath results in violent foaming so that the furnace is difficult to control.

It is therefore an object of my invention to provide apparatus for introducing materials into an open hearth furnace in such a manner as to overcome the above difliculties.

Another object is to provide such apparatus which eliminates excessive foaming.

These and other objects will be more apparent after referring to the following specification and attached drawings, in which:

FIGURE 1 is a schematic sectional view of an open hearth furnace equipped with the apparatus of my invention;

FIGURE 2 is an enlarged view, partly in section, of the solids injection lance of my invention;

FIGURE 3 is a view taken on the line IIIIII of FIG- URE 2; and

FIGURE 4 is a view taken on the line IVIV of FIG- URE 2.

Referring more particularly to the drawings reference numeral 2 indicates a steel producing open hearth furnace having a roof 4 and a hearth 6 for containing a molten metal bath 8 having a slag layer 10 thereon. A pair of spaced apart water cooled donuts 12 are arranged in the roof 4. A sleeve 14 is mounted for slidable movement in each donut 12. The sleeve 14 has a vertical opening 16 therethroug-h formed by an inner tube 18. A coaxial tube 20 surrounds the tube 18 and an intermediate coaxial tube 22 is positioned between the tubes 18 and 20. The tube 22 terminates short of the bottom of tubes 18 and 22 so as to provide a passageway therebetween. The tubes 18 and 20 are connected at their lower 3,236,511 Patented Feb. 22, 1966 ends in any suitable manner to make a water tight joint. The tubes 18 and 22 are connected at their upper end to provide a water tight joint. A water tight connection 23 is provided between the top of tube 20 and tube 22. An inlet Water connection 24 is provided at the top of tube 20 and an outlet water connection 26 is provided at the top of tube 22. A stationary tube or jet 28 extends downwardly into each donut 12.

A crushed limestone bin 30 and an ore bin 32 are arranged at a position spaced from the furnace 2 for receiving crushed limestone and ore in granular form. Gate valves 34 and 36 control discharge from bins 30 and 32 to rotary feeders 38 and 40, respectively. The rotary feeders are connected to supply lines 42 and 44 leading to the jets 28. Blowers 46 and 48 supply air under pressure to the supply lines 42 and 44. This conveying system is conventional equipment manufactured by Allen-Sherman-Holf Company of Wynnewood, Pennsylvania. Each sleeve 14 has a pair of ears at its upper end to which are attached the split ends of a wire rope 50. Each wire rope 50 is connected to a drum 52 which is rotated by motor 54.

An oxygen lance 56 of any standard construction is located adjacent each sleeve 14 and passes through a water cooled donut 58 into the furnace 2. Each lance 56 is connected by means of a wire rope 60 to a drum 62 which is rotated by a motor 64. The lance 56 is water cooled with cooling water being supplied thereto in the usual manner as shown. Oxygen is delivered into each lance 56 through a flexible conduit 66. It will be understood that each sleeve 14 is arranged in a set with an oxygen lance 56 and the number of sets may vary as desired.

In operation, after molten metal 8 and slag 10 have formed in the furnace 2 the oxygen lances 56 are lowered into the furnace by rotating the drums 62. As the lances near the bath the oxygen is turned on with the force of the oxygen creating a dish in the bath approximately 2 ft. in diameter directly beneath the lance so as to expose the slag metal interface. When it is desired to feed ore or limes-tone the sleeves 14 are lowered to a position above the slag. It is preferred that the bottom of the sleeve be within 1 ft. of the slag and in all cases the bottom of the sleeve will be closer to the slag than to the roof of the furnace when additions are being made. The gate valves 34 and/or 36 are opened and the blowers 46 and/or 48 turned on to deliver air borne solids through the jets 28 and sleeves 14 to the bath. Limestone may be injected through one sleeve and ore through the other sleeve, or limestone may be delivered through both sleeves or ore may be delivered through both sleeves as desired due to the requirements of the heat. I have found that the bottom of the oxygen lance 56 must be below the bottom of the sleeve 14 in each set and that the bottom of the sleeve 14 must be above the slag while the bottom of the oxygen lance may be in or above the slag. Also for efiicient operation the axes of the sleeve and oxygen jet in each set must be between 18 and 24 in. apart. When it is desired to discontinue feeding solid additions the gate valves 34 and 36 controlling the flow of material are closed and sleeves 14 are raised to a desired level above the bath to protect them from the furnace heat and also to prevent clogging of the bottom of the sleeve openings, then the blowers 46 and 48 are turned off. When it is no longer desired to feed oxygen the lances 56 will also be raised above the level of the roof. Also for best operation the velocity of the oxygen stream discharge should be greater than that of the velocity of the solids injection stream.

While one embodiment of my invention has been shown and described it will be apparent that other adaptations and modifications may be made without departing from the scope of the following claims.

I claim:

1. Apparatus for introducing materials into an open hearth furnace through the roof thereof comprising a generally vertical tube mounted with the bottom thereof adjacent said roof, means for delivering solid additive materials into said tube, a sleeve :slidably mounted on the bottom of said tube and extending downwardly toward a molten bath in said furnace, said sleeve and said tube 10 being in axial alignment, means for moving said sleeve between a position with its bottom adjacent said bath and a position with its bottom adjacent said roof, an oxygen lance extending downwardly through said roof adjacent said tube, and means for positioning said lance so that the outlet therefrom is below the outlet of said sleeve.

2. Apparatus, according to claim 1 in which the distance between the axes of said lance and tube is between 18 and 24 inches.

References Cited by the Examiner UNITED STATES PATENTS 1,822,944 9/1931 Wagstaff 2l4-18 2,991,173 7/ 1961 Trentini et al 26634 X 3,071,363 1/1963 Mackay 266-34 X FOREIGN PATENTS 637,833 3/1962 Canada.

15 WHITMORE A. WILTZ, Primary Examiner.

JAMES H. TAYMAN, JR., MORRIS O. WOLK,

Examiners. 

1. APPARATUS FOR INTRODUCING MATERIALS INTO AN OPEN HEARTH FURNACE THROUGH THE ROOF THEREOF COMPRISING A GENERALLY VERTICAL TUBE MOUNTED WITH THE BOTTOM THEREOF ADJACENT SAID ROOF, MEANS FOR DELIVERING SOLID ADDITIVE MATERIALS INTO SAID TUBE, A SLEEVE SLIDABLY MOUNTED ON THE BOTTOM OF SAID TUBE AND EXTENDING DOWNWARDLY TOWARD A MOLTEN BATH IN SAID FURNACE, SAID SLEEVE AND SAID TUBE BEING IN AXIAL ALIGNMENT, MEANS FOR MOVING SAID SLEEVE BETWEEN A POSITION WITH ITS BOTTOM ADJACENT SAID BATH AND A POSITION WITH ITS BOTTOM ADJACENT SAID ROOF, AN OXYGEN LANCE EXTENDING DOWNWARDLY THROUGH SAID ROOF ADJECENT SAID TUBE, AND MEANS FOR POSITIONING SAID LANCE SO THAT THE OUTLET THEREFROM IS BELOW THE OUTLET OF SAID SLEEVE. 